RE: SPICE compatibility issues

From: Muranyi, Arpad <arpad.muranyi_at_.....>
Date: Wed Jul 27 2005 - 10:41:57 PDT
Kevin,

First I feel I need to apologize for writing so much.  I am
usually not this active on email reflectors, but these subjects
are quite interesting, and close to my work...

You are making a good point.  I think we need to distinguish
between wanting to be compatible and making (automated)
translations as easy as possible.  But even for the latter,
the language must provide features which make the translation
easy, without having to come up with all kinds of wrappers,
hooplas and (excuse me my language) half-assed workarounds
to get it done.  Case in point, my "define and strings" thread.

Regarding making a library of standard models "that most
vendors, users and foundries agree on" this will be though.

Not that it couldn't be done, I think I have already seen
various university projects which have done it, or have even
automated it, but there is another issue, IC vendor proprietary
model files.  Companies like Intel will not make available their
transistor equations (and the associated process parameters) to
the public, so you will not be able to write a Verilog-AMS
module for such transistors.  The only reason you see HSPICE
models on occasions is because they can be encrypted (oooooouch,
I bit my mouth), but even for those you have to sign your life
away to get them.  Now, the funny thing is that even these
HSPICE models are kind of fake, because the Intel internal
SPICE simulator's transistor equations are completely different,
so in order to generate the HSPICE models, you have to translate
them.  And as with any translation, you have to make compromises,
which costs you accuracy...

Well, there, I spilled another can of worms...

Arpad
================================================================

 

-----Original Message-----
From: Kevin Cameron [mailto:kevin@sonicsinc.com] 
Sent: Wednesday, July 27, 2005 10:02 AM
To: Muranyi, Arpad
Cc: Geoffrey.Coram; verilog-ams@eda.org
Subject: Re: SPICE compatibility issues


I don't think it's the Verilog-AMS committee's job to work out exactly 
how to migrate old simulator netlists into Verilog-AMS. The language 
itself should (as much as possible) support re-writing the primitive 
models of  old simulators in portable Verilog-AMS - it's up to the 
vendors/users to do the translation.

Going forward it would be good to have a standard library of models for 
use with Verilog-AMS that have well defined parameters and behavior that 
most vendors, users and foundaries agree on - I'm assuming these will 
look pretty much like the current popular device models  used  by the 
various Spice simulators, but are unlikely to match any specific Spice 
exactly.

IMO the activity of defining and developing standard libraries should 
stay with Accellera, and the Verilog-AMS language development should 
move to an IEEE SystemVerilog subcommittee.

Kev.
Received on Wed Jul 27 10:42:02 2005

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